Starting from 2016 all phones, hotspot devices and Android tablets released and sold by T-Mobile support band 12. For the historical list of devices released in 2014 - 2016 visit this page.

Unlocked devices

The following unlocked phones support LTE band 12 and all other bands required to be compatible with T-Mobile network (LTE bands 2, 4 and 12, HSPA+ on AWS and 1900 MHz, and GSM on 1900 MHz). However band support is not the only requirement. T-Mobile issued a statement regarding band 12 unlocked phones: All Band 12 LTE devices on our network must support VoLTE, E911. In the first list below are unlocked phones that support VoLTE and band 12:

Phones that support T-Mobile Wi-Fi calling have next to them. Even though the phones above have been certified with T-Mobile, Wi-Fi calling is an optional feature for unlocked phones. If Wi-Fi calling is not supported by the phone you like and you are on a postpaid plan you can get a 4G LTE Cellspot that makes possible to place 3G and VoLTE calls via your Wi-Fi connection.

The following phones may support VoLTE on T-Mobile network however the manufacturers have not made it clear. Do you own one of the phones below and have a T-Mobile SIM card? Help us find out the status of VoLTE support: post
in /r/tmobile a screenshot showing LTE in the status bar while on a call using a phone below. Also please post model number shown in Settings > About.

LG V30 unlocked (US Cellular model confirmed to support T-Mobile VoLTE and Wi-Fi, waiting for an owner of the unlocked model to confirm the same)

Other LTE band 12 phones listed below do not support VoLTE. Due to lack of VoLTE support you won't be able to place and receive calls including 911 calls in some buildings and some outdoor areas where 2G GSM and 3G HSPA+ signal (marketed by T-Mobile as "4G") is too weak or non-existent while LTE band 12 is available. You will still have data connection so you can receive and place non-emergency calls via Google Hangouts app (using Google Voice number) or via T-Mobile Digits (duplicate or virtual number). To place an emergency call you will have to either go outdoors where 2G or 3G signal is available or disable LTE to make your phone roam on another GSM network.

Some carriers (AT&T, Sprint and US Cellular) sell phones that claim to support band 12 however in reality their phones may not have band 12 enabled. Due to this fact and other various issues with carrier-branded phones this section will only list phones that are confirmed to support band 12. If you confirm please make an announcement post in /r/tmobile (mention /u/sgteq in the comments to send me a notification). Also note that devices sold by carriers are typically SIM-locked (except Verizon devices). Check the unlocking policy with the carrier.

Few of the carrier branded US phones support VoLTE except on the network that sold them so the impaired calling warning applies to all such phones. The first list below confirms only that LTE band 12 data works.

Due to the huge number of phone models worldwide this site does not track devices sold outside of the US. To check band 12 support simply check phone specifications. Note that some sellers and manufacturers use outdated frequency notation (700/850/etc). There are seven LTE bands in the 700-800 MHz range so listing 700 MHz as a supported frequency is incredibly ambiguous. Use reliable sources of phone network specifications that list band numbers.

Virtually all phones sold outside of the US do not support VoLTE on T-Mobile network so the impaired calling warning applies to all such phones. If you learn about an international phone that supports T-Mobile VoLTE please make an announcement post in /r/tmobile (mention /u/sgteq in the comments to send me a notification).

Models that are known to support VoLTE on T-Mobile network and LTE band 12: